=over

=item $DEBUGGING

=item $^D
X<$^D> X<$DEBUGGING>

The current value of the debugging flags.  May be read or set.  Like its
L<command-line equivalent|perlrun/B<-D>I<letters>>, you can use numeric
or symbolic values, e.g. C<$^D = 10> or C<$^D = "st">.  See
L<perlrun/B<-D>I<number>>.  The contents of this variable also affects the
debugger operation.  See L<perldebguts/Debugger Internals>.

Mnemonic: value of B<-D> switch.

=back